10-globally-managed-devices.conf contained in wrong package

[Unit 193]

/usr/lib/NetworkManager/conf.d/10-globally-managed-devices.conf is installed from network-manager but without nplan it has no benefit, and breaks networking until you override it. Since the config is there to change how NetworkManager behaves in the presence of nplan, the configuration file itself should actually be contained in the nplan package.

[Mathieu Trudel-Lapierre (cyphermox)]

nplan is meant to be installed on all systems -- when both network-manager and nplan are installed, nplan also ships the right configuration to override the NetworkManager configuration and let it control all devices. This is required so that where appropriate, we can ship NetworkManager to handle just wireless devices but keep static configuration of the other interfaces, for example on servers.

nplan is shipping via ubuntu-standard. Is there a reason why it is not installed in your use case? Did this come up from an upgrade?

[Unit 193 (unit193)]

Right, I gathered that part. But then again so are things like resolved and snap which I consider optional (and the former has been breaking DNS in my VMs, 10-dns-resolved.conf made it more fun.)

I considered, based on the logic of "this configuration 'comes' for another package and breaks this package" should be enough, but yes I've had to track down as to why I had no networking with NM installed.

[Mathieu Trudel-Lapierre (cyphermox)]

Don't get me wrong, the upgrade issue this causes has to get fixed.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Brian Murray (brian-murray)]

I upgraded from 16.04 to 16.10 recently and ran into an issue where networking did not work until I created an empty file in /run/NetworkManager/conf.d/10-globally-managed-devices.conf.

nplan was installed after the upgrade:

 $ apt-cache policy nplan
nplan:
  Installed: 0.12
  Candidate: 0.12
  Version table:
 *** 0.12 500
        500 http://192.168.10.7/ubuntu yakkety/main amd64 Packages
        100 /var/lib/dpkg/status

[Brian Murray (brian-murray)]

I don't think many people are still upgrading from Xenial to Yakkety but this'll likely be important to fix for people upgrading from 16.04 to 18.04.

[Brian Murray (brian-murray)]

I reported a new bug about my issue - bug 1676547.

[Mathieu Trudel-Lapierre (cyphermox)]

The issue is that NM is shipping the file along with its override, but the override logic broke due to a backport of NM in xenial. I'm marking this bug here as duplicate of bug 1676547; since it has more of the necessary logs to debug this.

[Mathieu Trudel-Lapierre (cyphermox)]

Reverting duplicate to make the conclusion for this bug clearer:

This file belongs in NM and NM is supposed to make sure that it doesn't break things (which is why there is a bug for upgrade as bug 1676547). It should not be seen as an override but as Ubuntu shipping a default configuration meant to work on the majority of systems (see below).

nplan is in standard and on all systems, whereas NM doesn't normally exist on servers. nplan should not leave unnecessary files around -- on servers, the file in /usr/lib would be unnecessary -- it only makes sense if NetworkManager is installed.

On a typical desktop new install, netplan and NM would be installed, netplan would start at boot and write an override file to /run/NetworkManager/conf.d (as per its default configuration) to tell NM to manage all files. The networking behavior expected by our users would be maintained (ie. they don't need to run netplan, but we want to make it available and start educating on its use).

On earlier installed desktop systems, netplan gets installed on upgrade but likely does not start at boot (and regardless should not break networking before a reboot happens) and NM should write its "default config" and override it via /etc/NetworkManager/conf.d/10-globally-managed-devices.conf by postinst on its own upgrade. This is done to ensure networking is not broken during upgrade, and that old behavior is maintained on upgraded systems.

On servers, netplan is installed but not NetworkManager. netplan should not add unnecessary files to the install. Default behavior should already be maintained because the empty configuration shipped by default will not affect ifupdown/networkd; but users can start using netplan to configure their systems instead of ifupdown immediately.

The intent here is to make sure that NM behaves the right way given that nplan is on all systems, and that it does so following whether netplan is in use or not (as much as possible). netplan is meant to replace ifupdown for static network configuration, and to configure NetworkManager or networkd (depending on what is available) appropriately to drive the networking story requested by the user.